This invention relates to a machine useful for breaking very large pieces of scrap iron and steel which otherwise cannot economically be fragmented into the smaller sizes required for melting in metal processing furnaces. This machine is particularly adapted to fragmenting large, irregularly shaped scrap chunks of iron and steel that are produced by blast furnaces and steel manufacturing furnace operations.
In the manufacture of iron from ore in a blast furnace, molten slag floats upon the surface of molten iron produced in the furnace from the ore. The slag and the iron are separately tapped from the furnace and commercially used. However, at times the molten material in the interface area, which contains a mixture of slag and iron, is either tapped or is left over in some way so that it must be dealt with separately. That material, when removed from the furnace is solidified into very large, irregular chunks containing mixtures of slag and iron. While these chunks may vary in size and shape depending upon how and where the material is solidified, two forms are common. In one form the metal is poured into and solidified in circular mold-like depressions or slag pots to form large diameter roughly patty shapes which, for example, may be about 4 feet in diameter and roughly 11/2 feet thick. In another form, the metal may be in a slab-like shape which, for example, may be 4-5 feet wide, 6-8 feet long, roughly 12-18 inches thick and weigh in the neighborhood of 15-18 tons.
These heavy chunks are too large to be broken into smaller pieces and thrown back into the furnace for remelting and reprocessing. Ordinarily, pieces of about 5-8 inches are the maximum usable size for remelting in a furnace. Conventional hammer mills and other conventional breaking equipment cannot break those large chunks into small enough pieces for reuse. Consequently, the large chunks are simply discarded as waste material by-products of the blast furnace.
A similar problem arises in the manufacture of steel in open hearth or oxygen lance or electric steel making furnaces. From time to time, large, chunks of solidified scrap steel are produced. These chunks or pieces, which typically may be slab-like or more irregular in shape, are too large to economically break up in conventional equipment, such as in conventional hammer mills. Therefore, these chunks are discarded as waste material.
An enormous number of discarded, large, irregularly shaped, slab-like or patty-like pieces or chunks of iron, mixtures of iron and inclusions, or steel and the like has been accumulated in the vicinity of blast furnace and steel furnace facilities. Many of the pieces are so large, that even one or two pieces may be a full cargo for a flat bed truck. For example, a single piece may be 15 to 18 tons in weight. Such a piece is too large to commercially haul any distance or to economically break up into small pieces for reuse.
In some of the older iron and steel manufacturing facilities, the number of discarded large size scrap pieces that have accumulated over the years has created a storage problem. That is, dump areas are filled or nearly filled with scrap. Hauling away the large pieces, to make room for more, is too expensive. Meanwhile, the large amount of discarded iron and steel pieces is a rich, dormant mine containing already processed ferrous metal. That is, as compared with the processing of iron ore, the discarded pieces are already concentrated iron which no longer need complete, costly blast furnace treatment. Summarizing, the accumulated large chunk ferrous scrap material on the one hand, is an ecological and a storage problem and, on the other hand, is a valuable source of ferrous metal if the material can be broken economically into small, useable pieces.
In the past, breaking smaller size chunks of iron or steel has been accomplished by hammer mills. But, even the largest hammer mills are unable to handle very large size discarded scrap pieces. Skull cracker balls, lifted and dropped from cranes, can break up large pieces. But these require too much time, labor and crane machinery to make this economically feasible for continuous use in breaking very large pieces into useable small pieces. For example, a crane and ball might break up only 15 tons a day, which is not enough to be economically feasible.
Thus, there has been a need for a device capable of breaking very large size chunks or pieces of ferrous metal scrap into pieces that are small enough to be handled in conventional ferrous metal processing furnaces.